He may be correct in his first statement, but to rule out a possibly important role for God is in my view unjustified. It is certainly possible that God sets up and maintains or underpins the laws of physics and allows them to work, so that being able to explain the big bang in terms of physics is not inconsistent with there being a role for God.

As a scientist, you are continually questioning, rarely coming up with a definitive answer. The limitations of your own knowledge and expertise together with the beauty and mystery of life and the universe often fill you with a sense of profound humility. Thus, unequivocal assertions are not part of a genuine scientific quest.

Mathematics as applied to physics may be the queen of sciences according to Carl Friedrich Gauss, but it does not answer every scientific question. Chemistry, biology, psychology and the social sciences have their own ways of analysing the nature of reality which are complementary to those of physics and mathematics: indeed, they are not reducible to physics but their insights emerge at their own level of complexity.

Furthermore, many of the questions that are most crucial to us as human beings are not addressed adequately at all by science, such as the nature of beauty and love and how to live one's life – often philosophy or history or theology are better suited to help answer them.

The complementary nature of different questions and in particular of the difference between how and why are important. If M-theory does indeed turn out to enable a unified theory, Hawking may be able in future to say how the universe started, but as a physicist he cannot answer the question "why?"

This is well illustrated by John Polkinghorne's story about boiling a kettle: I can describe with physics how it boils in terms of the stove making its temperature rise; but why it is boiling is a different type of question altogether – most probably in my case because my wife is thirsty!

The so-called "God of the Gaps" is not part of modern religious faith. In this view, you invoked God to explain the inexplicable – at one time this would have been the weather or common diseases, and for Hawking apparently until recently the origin of the universe. Thus, when an alternative explanation arises, there is no longer any need for God.

The God followed by many people of a religious faith is not a God of the Gaps at all – rather a God who helps answer other nonscientific questions about why the universe and its amazing life exists and how to lead a good life. Also, they welcome the advances in understanding that modern science brings, since they reveal more of the incredible beauty, diversity and wonder of the nature of the universe.

You cannot prove whether God exists or not. But you can ask whether the existence or nonexistence of God is more consistent with your experience. It is up to each of us to reach our own conclusion, but for many of us it is and can make a profound and enriching difference to our lives.